The present embodiments relate to imaging a stent. In particular, images for implanting or viewing a cardiac stent are provided.
Coronary heart disease is the most common cause of death for men and women. To treat narrowing of the artery lumen due to accumulation of atheromatous plaques, a stent is implanted to expand and support the narrowing vessel. A stent is a fine mesh. A guide-wire is first introduced inside the artery. During implantation, the stent is supported by a balloon. An angioplasty balloon equipped with a stent is slid along the guide wire.
Stent deployment is monitored by X-ray fluoroscopy. Proper visualization of the stent, including the stent's location, surrounding tissue, and deployed geometry, is important to ensure the quality of stent expansion. However, some stents have less metal, so are less radiopaque. Drug eluting stents may also be less radiopaque than bare metal stents. Lower X-ray doses may be desired, but result in less image quality. As a result, stent visibility in X-ray images is challenging.
One technique for stent enhancement in X-ray fluoroscopy image sequences is based on motion compensated temporal integration of the stent images. To compensate for heart and/or breathing motion, image frames in an X-ray sequence are registered to align the stent. In order to assess the location of the stent, the angioplasty balloon is equipped with two heavily radiopaque markers. The motion of the stent is inferred from the motion of the highly contrasted balloon markers. Temporal averaging of all aligned images may allow preserving stent contrast in the image while suppressing the noise, leading to improved stent visibility. While the moving background in the registered image sequence is blurred, the stent is preserved.